What is the Microfilaria Blood Film test?

The Microfilaria Blood Film test is a microscopic examination of a blood sample to identify microfilariae, which are the larval forms of filarial worms. These parasites circulate in the blood in certain filarial infections.

The test involves preparing a stained blood film that is examined under a microscope by a trained specialist. It allows direct visual confirmation of parasitic infection and, in some cases, identification of the filarial species based on morphology.

This test is commonly used in the diagnosis of lymphatic filariasis and other filarial diseases, particularly in individuals with travel or residence history in endemic areas.

Why do I need a Microfilaria Blood Film test?

Filarial infections can cause chronic symptoms and may remain undiagnosed without specific testing. Blood film examination is a key diagnostic step.

You may need this test if you:

• Have lived in or travelled to tropical or subtropical regions

• Experience unexplained swelling of limbs or lymph nodes

• Have recurrent fever episodes

• Experience night sweats or fatigue

• Have eosinophilia on blood tests

• Have unexplained skin or eye symptoms

• Are being investigated for parasitic infection

The test helps confirm whether symptoms are related to a filarial parasite.

Benefits of the test

1. Direct detection of parasites
   Confirms infection by visual identification.

2. Supports diagnosis of filarial disease
   Essential in lymphatic filariasis investigation.

3. Useful in symptomatic and asymptomatic cases
   Can detect infection even without severe symptoms.

4. Widely used in tropical medicine
   Standard diagnostic method.

5. Simple blood-based testing
   Requires only one blood sample.

6. Helps guide further investigation
   Positive results support targeted follow-up.

7. Complements antibody testing
   Provides direct evidence of infection.

8. Reduces diagnostic uncertainty
   Confirms parasitic cause of symptoms.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• Blood sample taken by a clinician

• Blood film prepared and examined

• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Mobile phlebotomist attends your location

• Blood sample taken at home or hotel

• Sample transported to the laboratory for analysis

Timing of blood collection may be important, as some microfilariae circulate at specific times.

Your results explained

Negative result

• No microfilariae seen

• UK standard: Negative

• No evidence of filarial parasites in the blood

Positive result

• Microfilariae detected on blood film

• UK standard: Positive

• Confirms filarial infection

Further testing may be required to identify species and assess disease extent.